A passive optical network (PON) is a point-to-multipoint, fiber to the premises fiber-optic access network architecture in which unpowered optical splitters are used to facilitate a single optical fiber to serve multiple premises. For example, a single optical fiber may serve 16-128 premises. A PON may reduce the amount of optical fiber and central office equipment compared to point-to-point architectures. A PON may include an optical line terminal (OLT) at the service provider's central office and a number of optical network units (ONUs) near end users. Downstream signals are broadcast to the premises sharing multiple fibers with encryption to prevent eavesdropping.
A PON uses wavelength division multiplexing (WDM), using one wavelength, for example 1490 nm, for downstream traffic and another wavelength, for example 1310 nm, for upstream traffic. A 1550 nm wavelength is used for optional overlay services, for example radio frequency (RF) analog video.